Ornamenting and etching precious metal



UNITED STATES PATENT QFFICE.

HANNIBAL GOODWIN, OF NEWARK, NEIV JERSEY;

ORNAMENTING AND ETCHING PRECIOUS METAL.

SPECIFICATION forming part of Letters Patent No. 517,275, dated. March 27, 1894.

Application filed July 22, 1893- Serial No. 481,226. (No specimens-5 To all whom it may concern.-

Be it known that I, HANNIBAL Goonwm, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Ornamenting and Etching Precious Metals; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates more particularly to the decoration of the precious metals, silver and gold, by chemigraphic engraving and other chemical reactions.

The mordants hitherto more generally employed for biting into silver and gold have been unsuited for biting out designs applied by the usual methods of heliographic printing or by any of the usual transfer processes. For etching silver, either nitric acid or cyanide of potassium has been employed, and for etching gold, either aqua regia or cyanide of potassium. But these mordants are objectionable in that they are too solvent and disintegrating for the resisting matter applied as an insulator in the heliographic and trans fer methods above referred to.

I have discovered a mordant and a method of applying the same by which a successful and practical etching upon silver and gold is accomplished in connection with the above referred to methods of applying the design, followed by a decorative coloration in contrast to the parts that are etched away.

In carrying the invention into effect, I proceed as follows :-I either transfer to the metal surface a design in greasy ink by any of the well known transfer processes and reinforce the same by applying a suitable resisting dust; or, I cover the metal with a solution of sensitive asphaltum, expose the same to light under a negative or positive design and then develop the design by the removal of the unlighted portions of the asphaltum 3 or, I cover the metal with a film of sensitized albumen, expose the same to light under a negative or positive design and then, either before or after developing the design by the removal of theunlighted portions of the albumen apply a fatty ink or other equivalent matter, and then preferably reinforce the fatty or waxen design by incorporating therewith a dust of any suitable resisting matter;or, I may, by means of a tracing brush, apply to the metala design in any suitable resisting matter, or I may, finally, prepare the plate by any of the substitu tionary processes such as the application of a resisting matter either to the ground of the design followed by the removal of the adjacent resisting matter first applied or to those parts from which the first applied resisting matter has been removed, all by methods too Well known to require further description.

Having thus secured the design, I next suspend the plate as an anode in an electrolytic solution of iodine, preferably a solution of a salt of iodine, or a solution of a salt of iodine to which is added free iodine. I commonly employ a strong solution of iodide of potassium with the addition of free iodine as an electrolyte. The plate being suspended as an anode, I pass an electric current through said electrolyte, and as a result, a quick and perfect etching of the unprotected or uninsulated portions of the plate is obtained and without a solvent or disintegrating effect upon the resisting matter applied for insulation.

The electric current is very important in giving efliciency to the iodine as a mordant or corrosive of silver and gold, and especially with the latter. In fact,Iam not able to etch gold, excepting to secure an almost imperceptible tracery, unless I quicken its action by the electric current. Silver may be etched, though slowly by immersing it in a strong bath of iodine in the form of a very strong solution of iodide of potassium, containing free iodine; but, for obtaining speedier results the silver plate should be placed as an anode in the iodine electrolyte and subjected to the electric current. The plate, having been etched more or less, is cleaned 0%, resulting in the complete ornamental design, so far as formation is concerned. But to add to the decorative efiect, I proceed to give to the surface of the portions of the design etched away, a color in suitable contrast to the unetched surfaces. But it is very difficult to add a new color to gold by oxidation, While it is very easy to so color silver, and, therefore, in the case of a gold plate, etched as above, I deposit silver upon the etched out portions and then oxidize or platinize said deposited silver; or, I may deposit thereon any contrasting metal. In the case of a silver plate there is, of course, no necessity of depositing silver upon the surfaces of the portions etched out, and, therefore, I may proceed at once to oxidize or platinize them or deposit upon them another metal of a contrasting color. This deposition of metal or oxidation may be effected either before the resisting matter is removed from the plate, or after the cleaning of the plate. In this latter case, the oxidized or plated surfaces in relief may be stoned down until the metal of the body plate appears in contrast to the color given to the surfaces of the etched portions.

Instead of thus adding decorative effect to the etched out portions, I may apply thereto by well known processes, a niello or enamel filling, which is quite effective and in some cases more desirable. To add further decorative effect to these plates of precious metal, I apply to the parts left in relief a contrasting color, and to effect this I proceed as follows: Either after the preceding operations upon the etched portions, or independently of them, I cover up the said etched out portions with any suitable resisting matter, such as wax; then, I clean the surfaces in relief and then, either stain or oxidize, or platinize them, or deposit thereon a contrasting metal, and finally remove from the hollows the resisting matter by a suitable solvent.

Having thus described my invention, What I claim as new is-- 1. The process herein described of etching plates, which consists in applying to said plates a design in resisting matter, parts of the plates remaining bare, and then in subjecting the plates to the etching action of iodine, in an electrolytic bath, substantially as set forth.

2. The process herein described which consists in imposinga design in resisting matter upon a plate, part of the plate remaining bare, and then subjecting the bare part of said plate to the action of a salt of iodine combined with free iodine substantially as set forth.

3. The process herein described which consists in imposing a design in resisting matter upon precious metal, gold or silver, the surface thereof remaining, in parts, bare, and subjecting the bare parts to the action of iodide of potassium in solution with free iodine, substantially as set forth.

4. The process of etching gold or silver which consists in subjectinga plate of gold or silver as an anode of an electric pair to an electrolyte of an iodine salt substantially as set forth.

5. The process of etching precious metal, gold or silver, which consists in subjecting said plates to an electrolytic bath containing iodine in any of its forms in solution, as an anode of a galvanic pair, and subjected to an electric current, substantially as set forth.

6. The process of etching precious metal, gold or silver, which consists in subjecting said plates to an electrolytic bath containing in solution iodide of potassium with free iodine as an anode of a galvanic pair and subj ecting said plates thus immersed to an electric current, substantially as set forth.

7. The improved process of ornamenting plates of precious metal which consists in imposing a design in resisting matter upon a plate of gold or silver, parts of said plate remaining bare, then immersing said plates in a solution containing iodine in any suitable form or combination and etching out the bare parts substantially as set forth.

S. The improved process of ornamenting plates of precious metal which consists in imposing a design in resisting or insulating matter upon the plate, parts of the plate remaining bare, and then immersing said plate in an electrolyte containing iodide of potassium and free iodine as an anode and subjecting the plate to an electric current, substantially as set forth.

9. The process of ornamenting plates of precious metal, which consists in imposing a design in resisting matter upon the plate, parts of the latter remaining bare, then immersing said plate, in a bath containing iodine in any of its forms or combinations, as an anode, and subjecting said plate to an electric current and etching out the bare parts, then depositing an oxidizable metal upon the surface of the etched out parts, and finally oxidizing or platinizing the deposited metal, substantially as set forth.

10. The process of ornamenting plates of precious metal which consists in imposing a design in resisting matter upon a plate, parts of said plate remaining bare, then immersing said plate in a bath containing iodine in any of its forms or combinations, as an anode, and subjecting said plate to an electric current and etching out the bare parts, then removing the resisting matter and depositing an oxidizable metal upon the surface of said plate, then oxidizing or platinizing said deposited metal and stoning down or removing the projecting metal from the surfaces in relief, substantially as set forth.

11. In the process of ornamenting plates of precious metal, the process of forming raised or relief surfaces and ornamenting the same, which consists in imposing a design in resisting matter upon a plate, parts of said plate IIO remaining bare, then immersing said plate metal in contrast with that at the etched out [0 in a bath containing iodine in any of its parts, substantially as set forth.

forms, and subjecting the same to an electric In testimony that I claim the foregoing I current and thus etching out the bare parts, have hereunto set my hand this 19th day of then covering up the said etched out portions July, 1893.

with a suitable resisting matter such as Wax HANNIBAL GOODWIN. and cleaning off the surfaces in relief, then Witnesses: ornamenting said relief parts by oxidizing CHARLES H. PELL,

or staining them or depositing upon them JAs. A. FLEMING. 

